The MySpace Dragon Hoard (2008-2010)

Archive.org:

A wide-ranging collection of 490,000 mp3 files from MySpace.com, accomplished using unknown means by an anonymous academic study conducted between 2008 and 2010. […] Nearly every file in this item is no longer hosted at MySpace, due to a suspicious and low-key deletion/loss of data in 2018.

A bunch of music that was thought to be lost, has been found.